Apparatus for false-twisting multifilament threads and the like

ABSTRACT

A first false-twisting unit includes three axially parallel shafts of which two carry pairs of cooperating rotary friction members defining respective nips through which the travelling yarn passes for false-twisting and on a third of which a driven friction-drive roller is provided to drive the friction members. A second false-twisting unit includes a first roller coaxial with the friction-drive roller having an axial length substantially greater than the rotary friction members, and a second roller rotatably mounted in axial parallelism with the first roller and engaging the latter with its periphery to form with the first roller a second nip through which the travelling yarn passes to have a final false twist imparted to it and have its filaments moved into mutual parallelism. An arrangement is provided for traversing the second roller axially along the second roller.

United States Patent Enneking Dec. 11, 1973 [5 APPARATUS FOR FALSE-TWISTING 3,233,398 2/1966 Gilchrist 57/103 MULTIFILAMENT THREADSAND THE 3,313,096 4/1967 Marciniak 57/77.45

LIKE

Inventor: Heinrich Enneking, Karlsruhe,

Germany Industrie-Werke Karlsruhe Augsburg Aktiengesellschaft, Karlsruhe, Germany Filed: July 17, 1972 Appl. No.2 272,629

Assignee:

Foreign Application Priority Data Mar. 22, 1972 Germany P 22 13 851.8

References Cited UNITED STATES PATENTS l/l94l Pool 57/77.4 X 10/1958 Schrenk et al.... 57/773 3/1960 Haas, Jr. 57/7745 X Primary ExaminerJohn Petrakes Attarney-Michael S. Striker [5 7] ABSTRACT A first false-twisting unit includes three axially parallel shafts of which two carry pairs of cooperating rotary friction members defining respective nips through which the travelling yarn passes for false-twisting and on a third of which a driven friction-drive roller is provided to drive the friction members. A second falsetwisting unit includes a first roller coaxial with the friction-drive roller having an axial length substantially greater than the rotary friction members, and a second roller rotatably mounted in axial parallelism with the first roller and engaging the latter with its periphery to form with the first roller a second nip through which the travelling yarn passes to have a final false twist imparted to it and have its filaments moved into mutual parallelism. An arrangement is provided for traversing the second roller axially along the second roller.

7 Claims, 2 Drawing Figures lll APPARATUS FOR FALSE-TWISTING MULTIFILAMENT THREADS AND THE LIKE BACKGROUND OF THE INVENTION The present invention relates generally to the false twisting of multi-filament threads, yarns and the like, and more particularly to apparatus forcarrying out such false-twisting.

Many threads, yarns and the like must be false twisted for reasons well known in the industry. This is particularly although not exclusively true of synthetic threads or yarns. To carry out such false twisting various apparatus is already known from the prior art. One prior art proposal is a false-twisting apparatus of the Turbo Lansdale Machine Company, in which false twisting is effected by contact of a rotating body with the yarn or the like, and the rotating body in this case must have a high friction coefficient. Essentially this apparatus utilizes several parallel rotatable rings, discs or the like which are mounted for rotation about axes located in two or more different planes. The yarn, which word will be used hereafter to designate any kind of thread, filament or the like which is to be false twisted, is heated and thereupon passes through the nip between peripheries of cooperating pairs of the discs or the like. This imparts a false twist to the yarn as the latter is travelling out of and away from the heating device, in such a manner that the terminal pair of discs causes false twist to run in the direction towards the heating arrangement, that is opposite to the advancement of the yarn.

In this apparatus the yarn changes, as it leaves the terminal pair of discs (that is the final pair by which it is engaged) from twisted condition into a condition in which the individual filaments or capillary fibers of the yarn move to a condition of parallelism. In other words, on exiting from the nip of the final pair of discs, there is a sudden reduction to almost zero twist level. This means that where this transition takes place the thread performs, with respect to the final pair of rollers engaging it, not a rolling movement but a sliding frictional movement, with the resultthat the final pair of discs is subjected to very high wear.

Another prior-art apparatus for false-twisting purposes, also by the Turbo Lansdale Company, utilizes an axially relatively long roller whose periphery is covered with synthetic plastic material. A counter roller of lesser axial length and having a low coefficient of friction is pressed against the circumference of the longer roller, to form a nip therewith. The two rollers rotate in mutually opposite directions, but at least one of them is traversed axially with respect to the other. A heating arrangement is again provided and the yarn to be false twisted travels out of the heating arrangement and into and through the nip defined by the rollers, to be given a twist which runs back in the direction towards the heating arrangement. After leaving the nip, the filaments or fibers are again oriented in parallelism with one another clue to the traversing between the two rollers the point of contact between the two rollers, that is the location of the nip, constantly changes which results in a significant reduction of the wear on the rollers due to friction, simply because the friction at the point of contact, that is in the nip, changes from rolling friction to sliding friction. However, it has been found that this apparatus which thus provides an improvement in the undesirable high wear previously encountered, is

not capable of imparting as high a degree of twist, as in the previously mentioned appatatus. Thus, a high degree of twist which is frequently required cannot be obtained and the improvement created is offset by this drawback.

SUMMARY OF THE INVENTION It is, accordingly, an object of the present invention to provide a further improvement in false-twisting apparatus.

More particularly, his an object of the present invention to provide an improved false-twisting apparatus which affords the advantages of the two aforemen tioned prior-art apparatuses, but eliminates their disadvantages.

In pursuance of these objects and of others which will become apparent hereafter, one feature of the invention resides, in an apparatus for false-twisting travelling filamentary threads and the like, in a combination comprising a first false-twisting unit and a second falsetwisting unit. The first false-twisting unit includes three axially parallel shafts, pairs of cooperating rotary friction members provided on two of the shafts and forming respective first nips through which the travelling yarn passes to have a preliminary false twist imparted to it, and a driven friction-drive roller on the third of the shafts in driving engagement with the peripheries of the rotary friction members.

The second false-twisting unit includes a first roller coaxial with the friction-drive roller and having an axial length substantially greater than the rotary friction members, a second roller rotatably mounted in axial parallelism with the first roller and having a periphery engaging that of said first roller and forming a second nip through which the travelling yarn passes to have a final false-twist imparted to it and to have its filaments moved into mutual parallelism, and traversing means traversing the second roller axially along the first roller.

In essence, therefore, the present invention utilizes a combination of the .two approaches characteristic of the two aforementioned prior-art apparatuses. In so doing, however, it does not incorporate the disadvantages of these apparatuses but instead eliminates them.

The first falsetwisting unit produces a highly twisted thread and the second false-twisting unit receives this thread and without any difficulties, and particularly without any undesirably or unacceptably high degree of wear of the rollers, imparts to the: filaments or fibers of the thread the necessary or desired condition of parallelism.

The elimination of thedisadvantages inherent in the prior-art proposals by combining certain of their features is surprising and by no means obvious, as it would normally be expected that such a combination would inherently also include the disadvantages of the individual parts in the sum of the parts.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following de scription of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a somewhat diagrammatic side view illustrating an embodiment of the invention; and

FIG. 2 is a top plan view of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The thread to be false twisted, which may be a monofilament, or a multifilament thread, yarn or the like, is designated with reference numeral 1. In most instances, threads which are to be false twisted are of synthetic plastic material but this is not necessarily the case and no limitation to such a concept is intended. The thread is advanced first to the first false-twisting unit which is designated with reference numeral 2, and from the false-twisting unit 2 it goes to the false-twisting unit 4.

The false-twisting unit 2 essentially comprises three parallel shafts 2a, 2b and 2c. Axially adjacent one another and mounted on the shaft 2a are a friction disc 2d, a supporting or counter disc 2e and another friction disc 2f. These discs have freedom of rotation with respect to their shaft 2a. Another counter disc 2g, friction disc 2h and counter disc 2i are also rotatably mounted, axially adjacent one another on the shaft 20. Each of the friction disc forms a pair with one of the counter discs, and vice versa. The discs of each pair are in frictional engagement with their respective peripheries forming a nip through which the yarn 1 must pass.

The various discs are driven by a friction rollers 3 which is fixedly mounted on a shaft 2b driven in suitable manner for instance by a non-illustrated electromotor which is too well known to require detailed discussion. Motion is transmitted to the discs by engagement of the periphery of friction roller 3 with the discs 2d, 2f and 2h provided on the shafts 2a and 2c.

The filament l is heated in a heating arrangement which is not illustrated, being known per se, and advances into the nips between the pairs of friction and counter discs, of the false-twisting unit 2, being given a false twist 1a which runs back through the heating arrangement to the thread or yarn supply which is not illustrated.

Having been given the false twist la, the thread now advances in its travel through the false-twisting unit 4 which is essentially composed of a friction roller 4a cooperating with a disc or second roller 4b, the two rollers engaging one another with their peripheries to form an additional nip. The axial length of the roller 4a is substantially greater than that of the discs mounted on the shafts 2a and 20, because the roller 4b is to be traversed axially of the roller 40 and the large peripheral surface provided by the greater axial length of the roller 4a is therefore needed. It is advantageous to drive the unit 4 via the same electric drive which also drives the unit 2, in which case it is a very simple matter to have the shaft of the friction roller 4a be of one piece with, or be connected in motion transmitting relationship, the shaft 2b of the friction roller 3. Of course, the shaft of the friction roller 4a can be a separate shaft and can be driven by a separate drive, if desired.

The peripheries of the discs and the rollers are constituted of or covered with an appropriate material, preferably on a polyurethane basis, which affords the desired coefficient of friction. Such materials are for instance commercially available under the trade name Vulkollan.

As the thread 1 having the twist 1a arrives in the false-twisting unit 4, it is given another twist, but in opposite direction in this instance, In other words, the thread leaves the unit 4 slightly above the point of contact or nip between the rollers 4a and 4b which point is designated with reference character x in untwisted'condition in which its filaments or capillary fibers lb are completely or substantially in parallelism with one another. These filaments 1b then advance to a non-illustrated take-up which is not part of the invention.

It can be readily seen that the filament or thread 1 leaves the final pair of rollers 2f, 2i of the unit 2 in a straight-line path, that is that it moves in a straight path out of the nip between them, thus having minimum contact with the peripheries of these rollers and causing minimum wear of these peripheries. On the other hand, minimum wear is caused on the peripheries of the rollers of the unit 4 because of the constant change of the location of the nip due to the traversing of the roller 4b (indicated by the double-headed arrow in FIGS. 1 and 2) along the roller 4a, a relative motion, which incidentally could of course be reversed,

Means for traversing the roller 4b have been diagrammatically illustrated by the double-headed arrow, the shaft on which the roller 4b is mounted and the box showing such mounting; they are conventional and known per se and therefore not believed to require detailed illustration.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in an apparatus for false-twisting of filamentary threads and the like, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In an apparatus for false-twisting travelling filamentary threads and the like, a combination compris ing a first false-twisting unit including three axially parallel shafts, pairs of cooperating rotary friction members provided on two of said shafts and forming respective first nips through which the travelling yarn passes to have a preliminary false twist imparted to it, and a driven friction-drive roller on the third of said shafts in driving engagement with the peripheries of said rotary friction members; and a second false-twisting unit including a first roller coaxial with said friction-drive roller and having an axial length substantially greater than said rotary friction members, a second roller rotatably mounted in axial parallelism with said first roller and having a periphery engaging that of said first roller and forming a second nip through which the travelling yarn passes to have a final twist imparted to it and to have its filaments moved into mutual parallelism, and traversing means traversing said second roller axially along said first roller.

2. A combination as defined in claim 1, wherein said first roller includes a mounting shaft which is axially aligned with said third shaft.

3. A combination as defined in claim 2, wherein said third shaft and mounting shaft are of one piece.

4. A combination as defined in claim 1, wherein said rotary friction members are of substantially discshaped configuration.

5. A combination as defined in claim 4, wherein said rotary friction members have respective rounded peripheral edge faces, with the edge faces of the two rotary friction members of each pair being in contact and forming a respective first nip 6. A combination as defined in claim 1, wherein said rotary friction members are mounted on said two shafts with freedom of rotation relative "to the latter.

7. A combination as defined in claim 1, wherein said pairs of rotary friction members include a terminal pair; and wherein said second unit is arranged so that the yarn travels in a substantially straight path from the first nip of said terminal pair to said second nip formed by said first and second rollers. 

1. In an apparatus for false-twisting travelling filamentary threads and the like, a combination comprising a first falsetwisting unit including three axially parallel shafts, pairs of cooperating rotary friction members provided on two of said shafts and forming respective first nips through which the travelling yarn passes to have a preliminary false twist imparted to it, and a driven friction-drive roller on the third of said shafts in driving engagement with the peripheries of said rotary friction members; and a second false-twisting unit including a first roller coaxial with said friction-drive roller and having an axial length substantially greater than said rotary friction members, a second roller rotatably mounted in axial parallelism with said first roller and having a periphery engaging that of said first roller and forming a second nip through which the travelling yarn passes to have a final twist imparted to it and to have its filaments moved into mutual parallelism, and traversing means traversing said second roller axially along said first roller.
 2. A combination as defined in claim 1, wherein said first roller includes a mounting shaft which is axially aligned with said third shaft.
 3. A combination as defined in claim 2, wherein said third shaft and mounting shaft are of one piece.
 4. A combination as defined in claim 1, wherein said rotary friction members are of substantially disc-shaped configuration.
 5. A combination as defined in claim 4, wherein said rotary friction members have respective rounded peripheRal edge faces, with the edge faces of the two rotary friction members of each pair being in contact and forming a respective first nip.
 6. A combination as defined in claim 1, wherein said rotary friction members are mounted on said two shafts with freedom of rotation relative to the latter.
 7. A combination as defined in claim 1, wherein said pairs of rotary friction members include a terminal pair; and wherein said second unit is arranged so that the yarn travels in a substantially straight path from the first nip of said terminal pair to said second nip formed by said first and second rollers. 